The present invention relates to the generation of oxide pillar (PX) slot shapes in localized silicon-on-insulator (SOI) formation technology, and more specifically, to the automatic and orderly placement of rectangular PX slot shapes in complex sets of structures associated with localized SOI formation technology.
Today, in SOI formation technology, rectangular shapes (i.e., PX slot shapes) are placed on the edges of recess oxide (RX) shapes to allow for etching of slots and subsequent undercutting of epitaxial (epi) regions which form localized SOI regions. FIG. 1 illustrates a PX layer of an SOI structure according to the conventional art. As shown in FIG. 1, bulk silicon substrate 10 is provided where an epi region 12 is formed on top of the bulk silicon substrate 10 and a pad nitride film 14 is formed above the epi region 12. A PX layer 16 including a PX slot shape 11 is formed on top of a pad nitride film 14 and a PX opening 18 and a lateral trench 20 formed by reactive ion etching (RIE) is also provided.
In a conventional method of forming PX slot shapes, the placement of the shapes is performed manually during manufacturing. Typically, as shown in FIG. 2, the PX slot shapes formed in L-shapes, T-shapes, and vertical or horizontal shapes positioned in parallel. However, there are several problems associated with the conventional method. As shown in FIG. 2, since the PX slot shapes are manually placed on the RX shapes, some of the PX slot shapes may not be formed properly. For example, as shown in FIG. 2, the circled portion 15 indicates PX slot shapes positioned perpendicular to one another which are too close to one another and the circled portion 20 indicates PX slot shapes formed offset and in parallel, which are too close to one another.